| 2009-04-06 | @ SLN | 1 | W 6-4 | 1-0 | 2 | 45,832 | Paul Maholm | Adam Wainwright | John Grabow | Jason Motte | Matt Capps | 6 | 4 | 2 |
| 2009-04-07 | @ SLN | 2 | L 3-9 | 1-1 | 4 | 35,206 | Ian Snell | Kyle Lohse | Kyle Lohse | Ian Snell | | 9 | 13 | -4 |
| 2009-04-08 | @ SLN | 3 | W 7-4 | 2-1 | 3 | 35,535 | Zach Duke | Todd Wellemeyer | Zach Duke | Todd Wellemeyer | Matt Capps | 16 | 17 | -1 |
| 2009-04-09 | @ SLN | 4 | L 1-2 | 2-2 | 3 | 35,293 | Ross Ohlendorf | Chris Carpenter | Chris Carpenter | Ross Ohlendorf | Dennys Reyes | 17 | 19 | -2 |
| 2009-04-11 | @ CIN | 5 | W 10-2 | 2-3 | 6 | 22,276 | Paul Maholm | Johnny Cueto | Paul Maholm | Johnny Cueto | | 27 | 21 | 6 |
| 2009-04-12 | @ CIN | 6 | L 0-2 | 2-4 | 6 | 12,876 | Ian Snell | Aaron Harang | Aaron Harang | Ian Snell | | 27 | 23 | 4 |
| 2009-04-13 | vs HOU | 7 | W 7-0 | 3-4 | 6 | 38,411 | Zach Duke | Brian Moehler | Zach Duke | Brian Moehler | | 34 | 23 | 11 |
| 2009-04-15 | vs HOU | 8 | L 1-4 | 3-5 | 6 | 20,690 | Ross Ohlendorf | Mike Hampton | Mike Hampton | Ross Ohlendorf | | 35 | 27 | 8 |
| 2009-04-16 | vs HOU | 9 | L 3-6 | 3-6 | 6 | 13,877 | Jeff Karstens | Russ Ortiz | Wesley Wright | Sean Burnett | LaTroy Hawkins | 38 | 33 | 5 |
| 2009-04-17 | vs ATL | 10 | W 3-0 | 4-6 | 6 | 15,659 | Paul Maholm | Jair Jurrjens | Paul Maholm | Jair Jurrjens | Matt Capps | 41 | 33 | 8 |
| 2009-04-18 | vs ATL | 11 | W 10-0 | 5-6 | 5 | 20,755 | Ian Snell | Jo-Jo Reyes | Ian Snell | Jo-Jo Reyes | | 51 | 33 | 18 |
| 2009-04-19 | vs ATL | 12 | L 1-11 | 5-7 | 6 | 14,776 | Zach Duke | Javier Vazquez | Javier Vazquez | Zach Duke | | 52 | 44 | 8 |
| 2009-04-20 | vs FLO | 13 | W 8-0 | 6-7 | 4 | 8,790 | Ross Ohlendorf | Andrew Miller | Ross Ohlendorf | Andrew Miller | | 60 | 44 | 16 |
| 2009-04-21 | vs FLO | 14 | W 3-2 | 7-7 | 4 | 9,917 | Jeff Karstens | Anibal Sanchez | Jeff Karstens | Anibal Sanchez | Matt Capps | 63 | 46 | 17 |
| 2009-04-22 | vs FLO | 15 | W 7-4 | 8-7 | 4 | 10,655 | Paul Maholm | Ricky Nolasco | Paul Maholm | Ricky Nolasco | Matt Capps | 70 | 50 | 20 |
| 2009-04-24 | @ SDN | 16 | L 3-4 | 8-8 | 4 | 25,601 | Ian Snell | Kevin Correia | Edwin Moreno | Matt Capps | | 73 | 54 | 19 |
| 2009-04-25 | @ SDN | 17 | W 10-1 | 9-8 | 4 | 41,665 | Zach Duke | Shawn Hill | Zach Duke | Shawn Hill | | 83 | 55 | 28 |
| 2009-04-26 | @ SDN | 18 | W 8-3 | 10-8 | 4 | 30,848 | Ross Ohlendorf | Jake Peavy | Ross Ohlendorf | Jake Peavy | | 91 | 58 | 33 |
| 2009-04-27 | @ MIL | 19 | L 5-10 | 11-8 | 3 | 32,198 | Jeff Karstens | Braden Looper | Todd Coffey | Tyler Yates | | 96 | 68 | 28 |
| 2009-04-28 | @ MIL | 20 | L 5-6 | 11-9 | 4 | 26,594 | Paul Maholm | David Bush | Jorge Julio | Jesse Chavez | Trevor Hoffman | 101 | 74 | 27 |
| 2009-04-29 | @ MIL | 21 | L 0-1 | 11-10 | 4 | 29,791 | Ian Snell | Yovani Gallardo | Yovani Gallardo | Ian Snell | Carlos Villanueva | 101 | 75 | 26 |
| 2009-05-01 | vs CIN | 22 | L 0-4 | 11-11 | 4 | 14,238 | Zach Duke | Bronson Arroyo | Bronson Arroyo | Zach Duke | | 101 | 79 | 22 |
| 2009-05-02 | vs CIN | 23 | W 8-6 | 12-11 | 4 | 22,891 | Ross Ohlendorf | Micah Owings | Ross Ohlendorf | Micah Owings | | 109 | 85 | 24 |
| 2009-05-03 | vs CIN | 24 | L 0-5 | 12-12 | 5 | 13,670 | Jeff Karstens | Johnny Cueto | Johnny Cueto | Jeff Karstens | | 109 | 90 | 19 |
| 2009-05-04 | vs MIL | 25 | L 4-7 | 12-13 | 5 | 8,482 | Paul Maholm | Yovani Gallardo | Mark DiFelice | Matt Capps | Trevor Hoffman | 113 | 97 | 16 |
| 2009-05-05 | vs MIL | 26 | L 5-8 | 12-14 | 5 | 9,775 | Ian Snell | Jeff Suppan | Jeff Suppan | Ian Snell | Carlos Villanueva | 118 | 105 | 13 |
| 2009-05-06 | @ SLN | 27 | L 2-4 | 12-15 | 6 | 36,188 | Zach Duke | Mitchell Boggs | Kyle McClellan | Zach Duke | Ryan Franklin | 120 | 109 | 11 |
| 2009-05-07 | @ SLN | 28 | L 2-5 | 12-16 | 6 | 41,928 | Ross Ohlendorf | Todd Wellemeyer | Todd Wellemeyer | Ross Ohlendorf | Ryan Franklin | 122 | 114 | 8 |
| 2009-05-08 | @ NYN | 29 | L 3-7 | 12-17 | 6 | 38,496 | Jeff Karstens | Jonathon Niese | Bobby Parnell | Tyler Yates | | 125 | 121 | 4 |
| 2009-05-09 | @ NYN | 30 | L 1-10 | 12-18 | 6 | 39,769 | Paul Maholm | John Maine | John Maine | Paul Maholm | | 126 | 131 | -5 |
| 2009-05-10 | @ NYN | 31 | L 4-8 | 12-19 | 6 | 39,871 | Ian Snell | Livan Hernandez | Livan Hernandez | Ian Snell | | 130 | 139 | -9 |
| 2009-05-12 | vs SLN | 32 | W 7-1 | 13-19 | 6 | 11,718 | Zach Duke | Todd Wellemeyer | Zach Duke | Todd Wellemeyer | | 137 | 140 | -3 |
| 2009-05-13 | vs SLN | 33 | W 5-2 | 14-19 | 6 | 10,494 | Ross Ohlendorf | Joel Pineiro | Ross Ohlendorf | Joel Pineiro | Matt Capps | 142 | 142 | 0 |
| 2009-05-14 | vs SLN | 34 | L 1-5 | 14-20 | 6 | 12,347 | Jeff Karstens | Mitchell Boggs | Trever Miller | Jeff Karstens | | 143 | 147 | -4 |
| 2009-05-15 | vs COL | 35 | L 1-3 | 14-21 | 6 | 17,179 | Paul Maholm | Jorge de la Rosa | Alan Embree | Matt Capps | Huston Street | 144 | 150 | -6 |
| 2009-05-16 | vs COL | 36 | W 7-4 | 15-21 | 6 | 24,496 | Ian Snell | Aaron Cook | Sean Burnett | Matt Belisle | Matt Capps | 151 | 154 | -3 |
| 2009-05-17 | vs COL | 37 | W 11-4 | 15-22 | 6 | 14,545 | Zach Duke | Ubaldo Jimenez | Zach Duke | Alan Embree | | 162 | 158 | 4 |
| 2009-05-18 | @ WAS | 38 | W 12-7 | 15-23 | 6 | 14,549 | Ross Ohlendorf | Ross Detwiler | Ross Ohlendorf | Garrett Mock | | 174 | 165 | 9 |
| 2009-05-19 | @ WAS | 39 | W 8-5 | 16-23 | 6 | 18,579 | Jeff Karstens | Shairon Martis | Tom Gorzelanny | Joe Beimel | | 182 | 170 | 12 |
| 2009-05-20 | @ WAS | 40 | W 2-1 | 17-23 | 6 | 17,854 | Paul Maholm | John Lannan | John Grabow | Joel Hanrahan | Matt Capps | 184 | 171 | 13 |
| 2009-05-21 | @ WAS | 41 | L 4-5 | 17-24 | 6 | 17,816 | Ian Snell | Craig Stammen | Julian Tavarez | Tom Gorzelanny | Joel Hanrahan | 188 | 176 | 12 |
| 2009-05-22 | @ CHA | 42 | L 0-2 | 17-25 | 6 | 23,347 | Zach Duke | Gavin Floyd | Gavin Floyd | Zach Duke | Bobby Jenks | 188 | 178 | 10 |
| 2009-05-23 | @ CHA | 43 | L 0-4 | 17-26 | 6 | 32,389 | Ross Ohlendorf | Clayton Richard | Clayton Richard | Ross Ohlendorf | | 188 | 182 | 6 |
| 2009-05-24 | @ CHA | 44 | W 4-3 | 18-26 | 6 | 28,309 | Jeff Karstens | Mark Buehrle | John Grabow | Bobby Jenks | Matt Capps | 192 | 185 | 7 |
| 2009-05-25 | @ CHN | 45 | W 10-8 | 18-27 | 6 | 38,942 | Paul Maholm | Ryan Dempster | Tom Gorzelanny | Neal Cotts | Sean Burnett | 202 | 193 | 9 |
| 2009-05-26 | @ CHN | 46 | L 1-6 | 18-28 | 6 | 38,303 | Ian Snell | Sean Marshall | Sean Marshall | Ian Snell | | 203 | 199 | 4 |
| 2009-05-27 | @ CHN | 47 | L 2-5 | 18-29 | 6 | 38,314 | Zach Duke | Carlos Zambrano | Carlos Marmol | Jesse Chavez | Kevin Gregg | 205 | 204 | 1 |
| 2009-05-29 | vs HOU | 48 | L 1-6 | 18-30 | 6 | 18,236 | Ross Ohlendorf | Brian Moehler | Brian Moehler | Ross Ohlendorf | | 206 | 210 | -4 |
| 2009-05-30 | vs HOU | 49 | W 7-4 | 19-30 | 6 | 37,167 | Jeff Karstens | Wandy Rodriguez | Jeff Karstens | Wandy Rodriguez | Matt Capps | 213 | 214 | -1 |
| 2009-05-31 | vs HOU | 50 | L 1-2 | 19-31 | 6 | 19,566 | Paul Maholm | Mike Hampton | Mike Hampton | Paul Maholm | LaTroy Hawkins | 214 | 216 | -2 |
| 2009-06-01 | vs NYN | 51 | W 8-5 | 20-31 | 6 | 11,812 | Ian Snell | Livan Hernandez | Tom Gorzelanny | J.J. Putz | Matt Capps | 222 | 221 | 1 |
| 2009-06-02 | vs NYN | 52 | W 3-1 | 21-31 | 6 | 10,459 | Zach Duke | Johan Santana | Zach Duke | Johan Santana | Matt Capps | 225 | 222 | 3 |
| 2009-06-04 | vs NYN | 53 | W 11-6 | 21-32 | 6 | 20,683 | Ross Ohlendorf | Mike Pelfrey | Steven Jackson | Mike Pelfrey | | 236 | 228 | 8 |
| 2009-06-05 | @ HOU | 54 | L 1-9 | 21-33 | 6 | 26,222 | Jeff Karstens | Mike Hampton | Mike Hampton | Jeff Karstens | | 237 | 237 | 0 |
| 2009-06-06 | @ HOU | 55 | W 6-4 | 22-33 | 6 | 26,099 | Paul Maholm | Roy Oswalt | Paul Maholm | Roy Oswalt | Matt Capps | 243 | 241 | 2 |
| 2009-06-07 | @ HOU | 56 | L 4-6 | 22-34 | 6 | 25,729 | Ian Snell | Felipe Paulino | Jeff Fulchino | Steven Jackson | LaTroy Hawkins | 247 | 247 | 0 |
| 2009-06-08 | @ ATL | 57 | L 6-7 | 22-35 | 6 | 21,856 | Zach Duke | Kenshin Kawakami | Kris Medlen | Jeff Karstens | | 253 | 254 | -1 |
| 2009-06-09 | @ ATL | 58 | L 3-4 | 22-36 | 6 | 20,124 | Ross Ohlendorf | Derek Lowe | Derek Lowe | Sean Burnett | Rafael Soriano | 256 | 258 | -2 |
| 2009-06-10 | @ ATL | 59 | W 3-2 | 23-36 | 6 | 21,610 | Charlie Morton | Jair Jurrjens | Jeff Karstens | Jair Jurrjens | Matt Capps | 259 | 260 | -1 |
| 2009-06-11 | @ ATL | 60 | W 3-1 | 24-36 | 6 | 29,331 | Paul Maholm | Javier Vazquez | Steven Jackson | Rafael Soriano | Matt Capps | 262 | 261 | 1 |
| 2009-06-12 | vs DET | 61 | L 1-3 | 24-37 | 6 | 18,369 | Ian Snell | Rick Porcello | Rick Porcello | Ian Snell | Fernando Rodney | 263 | 264 | -1 |
| 2009-06-13 | vs DET | 62 | W 9-3 | 25-37 | 6 | 31,411 | Zach Duke | Armando Galarraga | Zach Duke | Armando Galarraga | | 272 | 267 | 5 |
| 2009-06-14 | vs DET | 63 | W 6-3 | 26-37 | 6 | 27,565 | Ross Ohlendorf | Dontrelle Willis | Ross Ohlendorf | Dontrelle Willis | Matt Capps | 278 | 270 | 8 |
| 2009-06-16 | @ MIN | 64 | L 2-8 | 26-38 | 6 | 25,351 | Paul Maholm | Glen Perkins | Glen Perkins | Paul Maholm | | 280 | 278 | 2 |
| 2009-06-17 | @ MIN | 65 | W 8-2 | 27-38 | 6 | 30,057 | Ian Snell | Francisco Liriano | Ian Snell | Francisco Liriano | | 288 | 280 | 8 |
| 2009-06-18 | @ MIN | 66 | L 1-5 | 27-39 | 6 | 30,670 | Zach Duke | Nick Blackburn | Nick Blackburn | Zach Duke | | 289 | 285 | 4 |
| 2009-06-19 | @ COL | 67 | L 3-7 | 27-40 | 6 | 31,248 | Ross Ohlendorf | Jason Marquis | Jason Marquis | Ross Ohlendorf | | 292 | 292 | 0 |
| 2009-06-20 | @ COL | 68 | L 7-9 | 27-41 | 6 | 32,137 | Charlie Morton | Jason Hammel | Huston Street | Jesse Chavez | | 299 | 301 | -2 |
| 2009-06-21 | @ COL | 69 | L 4-5 | 27-42 | 6 | 44,131 | Paul Maholm | Jorge de la Rosa | Jorge de la Rosa | Paul Maholm | Huston Street | 303 | 306 | -3 |
| 2009-06-23 | vs CLE | 70 | L 4-5 | 27-43 | 6 | 19,109 | Ian Snell | David Huff | David Huff | Ian Snell | Kerry Wood | 307 | 311 | -4 |
| 2009-06-24 | vs CLE | 71 | W 10-6 | 27-44 | 6 | 20,162 | Zach Duke | Carl Pavano | Zach Duke | Carl Pavano | | 317 | 317 | 0 |
| 2009-06-25 | vs CLE | 72 | W 3-2 | 28-44 | 6 | 30,120 | Ross Ohlendorf | Cliff Lee | Matt Capps | Matt Herges | | 320 | 319 | 1 |
| 2009-06-26 | vs KCA | 73 | W 5-3 | 29-44 | 6 | 18,458 | Virgil Vasquez | Gil Meche | Virgil Vasquez | Gil Meche | Matt Capps | 325 | 322 | 3 |
| 2009-06-27 | vs KCA | 74 | W 6-2 | 30-44 | 6 | 36,032 | Paul Maholm | Bruce Chen | Paul Maholm | Bruce Chen | | 331 | 324 | 7 |
| 2009-06-28 | vs KCA | 75 | L 2-3 | 30-45 | 6 | 25,888 | Charlie Morton | Zack Greinke | Zack Greinke | Charlie Morton | Joakim Soria | 333 | 327 | 6 |
| 2009-06-29 | vs CHN | 76 | L 1-3 | 30-46 | 6 | 15,400 | Zach Duke | Rich Harden | Rich Harden | Zach Duke | Kevin Gregg | 334 | 330 | 4 |
| 2009-06-30 | vs CHN | 77 | W 3-0 | 31-46 | 6 | 17,054 | Ross Ohlendorf | Ted Lilly | Ross Ohlendorf | Ted Lilly | Matt Capps | 337 | 330 | 7 |
| 2009-07-01 | vs CHN | 78 | L 1-4 | 31-47 | 6 | 15,770 | Virgil Vasquez | Randy Wells | Randy Wells | Virgil Vasquez | Kevin Gregg | 338 | 334 | 4 |
| 2009-07-02 | vs NYN | 79 | L 8-9 | 31-48 | 6 | 14,321 | Paul Maholm | Tim Redding | Francisco Rodriguez | Matt Capps | | 346 | 343 | 3 |
| 2009-07-03 | @ FLO | 80 | W 7-4 | 32-48 | 6 | 16,114 | Charlie Morton | Chris Volstad | Charlie Morton | Chris Volstad | | 353 | 347 | 6 |
| 2009-07-04 | @ FLO | 81 | L 3-5 | 32-49 | 6 | 25,303 | Zach Duke | Andrew Miller | Andrew Miller | Zach Duke | Dan Meyer | 356 | 352 | 4 |
| 2009-07-05 | @ FLO | 82 | L 0-5 | 32-50 | 6 | 13,287 | Ross Ohlendorf | Ricky Nolasco | Ricky Nolasco | Ross Ohlendorf | | 356 | 357 | -1 |
| 2009-07-06 | @ HOU | 83 | L 1-4 | 32-51 | 6 | 26,834 | Virgil Vasquez | Mike Hampton | Mike Hampton | Virgil Vasquez | Jose Valverde | 357 | 361 | -4 |
| 2009-07-07 | @ HOU | 84 | W 6-3 | 33-51 | 6 | 27,142 | Paul Maholm | Brian Moehler | Paul Maholm | Brian Moehler | Matt Capps | 363 | 364 | -1 |
| 2009-07-08 | @ HOU | 85 | L 0-5 | 33-52 | 6 | 29,243 | Charlie Morton | Wandy Rodriguez | Wandy Rodriguez | Charlie Morton | | 363 | 369 | -6 |
| 2009-07-10 | @ PHI | 86 | L 2-3 | 33-53 | 6 | 45,246 | Zach Duke | Joe Blanton | Joe Blanton | Zach Duke | Brad Lidge | 365 | 372 | -7 |
| 2009-07-11 | @ PHI | 87 | L 7-8 | 33-54 | 6 | 45,209 | Ross Ohlendorf | Cole Hamels | Tyler Walker | Matt Capps | | 372 | 380 | -8 |
| 2009-07-12 | @ PHI | 88 | L 2-5 | 33-55 | 8 | 45,245 | Virgil Vasquez | J.A. Happ | J.A. Happ | Virgil Vasquez | | 374 | 385 | -11 |
| 2009-07-17 | vs SFN | 89 | W 2-1 | 34-55 | 6 | 26,709 | Paul Maholm | Tim Lincecum | Evan Meek | Bob Howry | | 376 | 386 | -10 |
| 2009-07-18 | vs SFN | 90 | W 2-0 | 35-55 | 6 | 37,023 | Charlie Morton | Barry Zito | Charlie Morton | Barry Zito | Matt Capps | 378 | 386 | -8 |
| 2009-07-19 | vs SFN | 91 | L 3-4 | 35-56 | 6 | 24,842 | Zach Duke | Matt Cain | Matt Cain | Zach Duke | Brian Wilson | 381 | 390 | -9 |
| 2009-07-20 | vs MIL | 92 | W 8-5 | 36-56 | 6 | 11,471 | Ross Ohlendorf | Mike Burns | Ross Ohlendorf | Mike Burns | | 389 | 395 | -6 |
| 2009-07-21 | vs MIL | 93 | L 0-2 | 36-57 | 6 | 16,184 | Virgil Vasquez | Braden Looper | Braden Looper | Virgil Vasquez | Trevor Hoffman | 389 | 397 | -8 |
| 2009-07-22 | vs MIL | 94 | W 8-7 | 37-57 | 6 | 21,186 | Paul Maholm | Jeff Suppan | Matt Capps | Mitch Stetter | | 397 | 404 | -7 |
| 2009-07-23 | @ ARI | 95 | L 4-11 | 38-57 | 6 | 24,008 | Charlie Morton | Dan Haren | Juan Gutierrez | Evan Meek | | 401 | 415 | -14 |
| 2009-07-24 | @ ARI | 96 | W 10-3 | 38-58 | 6 | 24,911 | Zach Duke | Yusmeiro Petit | Zach Duke | Yusmeiro Petit | | 411 | 418 | -7 |
| 2009-07-25 | @ ARI | 97 | L 0-7 | 38-59 | 6 | 26,037 | Ross Ohlendorf | Doug Davis | Doug Davis | Ross Ohlendorf | | 411 | 425 | -14 |
| 2009-07-26 | @ ARI | 98 | L 0-9 | 38-60 | 6 | 27,507 | Virgil Vasquez | Max Scherzer | Max Scherzer | Virgil Vasquez | | 411 | 434 | -23 |
| 2009-07-27 | @ SFN | 99 | L 2-4 | 38-61 | 6 | 40,008 | Paul Maholm | Tim Lincecum | Tim Lincecum | Paul Maholm | | 413 | 438 | -25 |
| 2009-07-28 | @ SFN | 100 | L 2-3 | 38-62 | 6 | 35,972 | Charlie Morton | Barry Zito | Sergio Romo | Charlie Morton | Brian Wilson | 415 | 441 | -26 |
| 2009-07-29 | @ SFN | 101 | L 0-1 | 38-63 | 6 | 37,582 | Zach Duke | Matt Cain | Brian Wilson | Matt Capps | | 415 | 442 | -27 |
| 2009-07-31 | vs WAS | 102 | W 5-4 | 39-63 | 6 | 23,363 | Ross Ohlendorf | John Lannan | Ross Ohlendorf | John Lannan | Matt Capps | 420 | 446 | -26 |
| 2009-08-01 | vs WAS | 103 | W 11-6 | 39-64 | 6 | 26,855 | Virgil Vasquez | Craig Stammen | Virgil Vasquez | Craig Stammen | | 431 | 452 | -21 |
| 2009-08-02 | vs WAS | 104 | L 3-5 | 39-65 | 6 | 21,894 | Paul Maholm | Collin Balester | Sean Burnett | Paul Maholm | Mike MacDougal | 434 | 457 | -23 |
| 2009-08-03 | vs WAS | 105 | L 4-8 | 39-66 | 6 | 11,630 | Charlie Morton | Garrett Mock | Tyler Clippard | Charlie Morton | Mike MacDougal | 438 | 465 | -27 |
| 2009-08-04 | vs ARI | 106 | L 0-6 | 39-67 | 6 | 11,294 | Zach Duke | Yusmeiro Petit | Yusmeiro Petit | Zach Duke | | 438 | 471 | -33 |
| 2009-08-05 | vs ARI | 107 | L 3-4 | 39-68 | 6 | 11,470 | Ross Ohlendorf | Doug Davis | Doug Davis | Joel Hanrahan | Chad Qualls | 441 | 475 | -34 |
| 2009-08-06 | vs ARI | 108 | L 6-11 | 40-68 | 6 | 17,311 | Kevin Hart | Max Scherzer | Jon Rauch | Steven Jackson | | 447 | 486 | -39 |
| 2009-08-07 | vs SLN | 109 | L 4-6 | 40-69 | 6 | 24,854 | Paul Maholm | Chris Carpenter | Chris Carpenter | Jose Ascanio | Ryan Franklin | 451 | 492 | -41 |
| 2009-08-08 | vs SLN | 110 | L 3-5 | 40-70 | 6 | 38,593 | Charlie Morton | Adam Wainwright | Adam Wainwright | Charlie Morton | Ryan Franklin | 454 | 497 | -43 |
| 2009-08-09 | vs SLN | 111 | L 3-7 | 40-71 | 6 | 24,369 | Zach Duke | Joel Pineiro | Joel Pineiro | Matt Capps | Kyle McClellan | 457 | 504 | -47 |
| 2009-08-11 | @ COL | 112 | W 7-3 | 41-71 | 6 | 35,212 | Ross Ohlendorf | Jhoulis Chacin | Ross Ohlendorf | Jhoulis Chacin | | 464 | 507 | -43 |
| 2009-08-12 | @ COL | 113 | L 0-8 | 41-72 | 6 | 29,430 | Kevin Hart | Ubaldo Jimenez | Ubaldo Jimenez | Kevin Hart | | 464 | 515 | -51 |
| 2009-08-13 | @ COL | 114 | L 1-10 | 41-73 | 6 | 27,619 | Paul Maholm | Jason Marquis | Jason Marquis | Paul Maholm | | 465 | 525 | -60 |
| 2009-08-14 | @ CHN | 115 | L 2-17 | 42-73 | 6 | 41,619 | Charlie Morton | Randy Wells | Randy Wells | Charlie Morton | | 467 | 542 | -75 |
| 2009-08-15 | @ CHN | 116 | L 1-3 | 42-74 | 6 | 41,197 | Zach Duke | Tom Gorzelanny | Tom Gorzelanny | Zach Duke | Kevin Gregg | 468 | 545 | -77 |
| 2009-08-17 | vs MIL | 117 | W 9-5 | 43-74 | 6 | 12,478 | Kevin Hart | Carlos Villanueva | Kevin Hart | Carlos Villanueva | | 477 | 550 | -73 |
| 2009-08-18 | vs MIL | 118 | W 5-2 | 44-74 | 6 | 12,188 | Ross Ohlendorf | Manny Parra | Ross Ohlendorf | Manny Parra | | 482 | 552 | -70 |
| 2009-08-19 | vs MIL | 119 | W 3-1 | 45-74 | 6 | 12,630 | Paul Maholm | Yovani Gallardo | Paul Maholm | Yovani Gallardo | Matt Capps | 485 | 553 | -68 |
| 2009-08-21 | vs CIN | 120 | W 5-2 | 46-74 | 6 | 22,725 | Charlie Morton | Micah Owings | Charlie Morton | Micah Owings | Matt Capps | 490 | 555 | -65 |
| 2009-08-22 | vs CIN | 121 | W 12-2 | 46-75 | 6 | 32,570 | Zach Duke | Justin Lehr | Zach Duke | Justin Lehr | | 502 | 557 | -55 |
| 2009-08-23 | vs CIN | 122 | L 1-4 | 46-76 | 6 | 21,209 | Kevin Hart | Homer Bailey | Homer Bailey | Kevin Hart | Francisco Cordero | 503 | 561 | -58 |
| 2009-08-25 | vs PHI | 123 | W 6-4 | 47-76 | 6 | 17,049 | Ross Ohlendorf | Joe Blanton | Matt Capps | Brad Lidge | | 509 | 565 | -56 |
| 2009-08-26 | vs PHI | 124 | L 1-4 | 47-77 | 6 | 17,403 | Paul Maholm | Cole Hamels | Ryan Madson | Steven Jackson | | 510 | 569 | -59 |
| 2009-08-27 | vs PHI | 125 | W 3-2 | 48-77 | 6 | 24,470 | Charlie Morton | J.A. Happ | Denny Bautista | J.A. Happ | Matt Capps | 513 | 571 | -58 |
| 2009-08-28 | @ MIL | 126 | L 6-8 | 48-78 | 6 | 34,438 | Zach Duke | Manny Parra | Manny Parra | Zach Duke | Trevor Hoffman | 519 | 579 | -60 |
| 2009-08-29 | @ MIL | 127 | L 3-7 | 48-79 | 6 | 41,773 | Kevin Hart | Yovani Gallardo | Claudio Vargas | Kevin Hart | | 522 | 586 | -64 |
| 2009-08-30 | @ MIL | 128 | L 1-4 | 48-80 | 6 | 41,157 | Ross Ohlendorf | Jeff Suppan | Jeff Suppan | Ross Ohlendorf | Trevor Hoffman | 523 | 590 | -67 |
| 2009-08-31 | @ CIN | 129 | L 3-4 | 48-82 | 8 | 13,051 | Daniel McCutchen | Kip Wells | Nick Masset | Jesse Chavez | | 526 | 594 | -68 |
| 2009-08-31 | @ CIN | 130 | L 3-6 | 48-82 | 8 | 9,087 | Paul Maholm | Johnny Cueto | Johnny Cueto | Paul Maholm | Francisco Cordero | 529 | 600 | -71 |
| 2009-09-01 | @ CIN | 131 | L 5-11 | 49-82 | 6 | 10,304 | Charlie Morton | Justin Lehr | Justin Lehr | Charlie Morton | Micah Owings | 534 | 611 | -77 |
| 2009-09-02 | @ CIN | 132 | L 3-5 | 49-83 | 6 | 11,541 | Zach Duke | Homer Bailey | Homer Bailey | Zach Duke | Francisco Cordero | 537 | 616 | -79 |
| 2009-09-04 | vs SLN | 133 | L 7-14 | 50-83 | 6 | 15,258 | Kevin Hart | Adam Wainwright | Adam Wainwright | Kevin Hart | | 544 | 630 | -86 |
| 2009-09-05 | vs SLN | 134 | L 1-2 | 50-84 | 6 | 27,071 | Ross Ohlendorf | Mitchell Boggs | Blake Hawksworth | Matt Capps | Ryan Franklin | 545 | 632 | -87 |
| 2009-09-06 | vs SLN | 135 | W 6-5 | 51-84 | 6 | 19,274 | Paul Maholm | Joel Pineiro | Jesse Chavez | Ryan Franklin | | 551 | 637 | -86 |
| 2009-09-07 | vs CHN | 136 | L 2-4 | 51-85 | 6 | 14,673 | Daniel McCutchen | Ted Lilly | Ted Lilly | Daniel McCutchen | Carlos Marmol | 553 | 641 | -88 |
| 2009-09-08 | vs CHN | 137 | L 4-9 | 51-86 | 6 | 17,862 | Zach Duke | Ryan Dempster | Ryan Dempster | Zach Duke | | 557 | 650 | -93 |
| 2009-09-09 | vs CHN | 138 | L 5-8 | 51-87 | 6 | 10,899 | Kevin Hart | Carlos Zambrano | Carlos Zambrano | Kevin Hart | Carlos Marmol | 562 | 658 | -96 |
| 2009-09-11 | @ HOU | 139 | L 1-9 | 51-88 | 6 | 31,302 | Charlie Morton | Bud Norris | Bud Norris | Charlie Morton | | 563 | 667 | -104 |
| 2009-09-12 | @ HOU | 140 | L 2-4 | 51-89 | 6 | 35,213 | Ross Ohlendorf | Brian Moehler | Jeff Fulchino | Ross Ohlendorf | Jose Valverde | 565 | 671 | -106 |
| 2009-09-13 | @ HOU | 141 | W 2-1 | 52-89 | 6 | 34,405 | Paul Maholm | Felipe Paulino | Paul Maholm | Felipe Paulino | Matt Capps | 567 | 672 | -105 |
| 2009-09-14 | @ LAN | 142 | L 2-6 | 52-90 | 6 | 42,045 | Daniel McCutchen | Jon Garland | Jon Garland | Daniel McCutchen | | 569 | 678 | -109 |
| 2009-09-15 | @ LAN | 143 | L 4-5 | 52-91 | 6 | 52,562 | Zach Duke | Randy Wolf | Ronald Belisario | Phil Dumatrait | | 573 | 683 | -110 |
| 2009-09-16 | @ LAN | 144 | L 1-3 | 52-92 | 6 | 53,193 | Kevin Hart | Hiroki Kuroda | Hiroki Kuroda | Kevin Hart | Jonathan Broxton | 574 | 686 | -112 |
| 2009-09-18 | vs SDN | 145 | W 5-1 | 53-92 | 6 | 26,178 | Charlie Morton | Tim Stauffer | Charlie Morton | Tim Stauffer | | 579 | 687 | -108 |
| 2009-09-19 | vs SDN | 146 | L 1-2 | 53-93 | 6 | 20,379 | Ross Ohlendorf | Clayton Richard | Luke Gregerson | Phil Dumatrait | Heath Bell | 580 | 689 | -109 |
| 2009-09-20 | vs SDN | 147 | L 0-4 | 53-94 | 6 | 24,028 | Paul Maholm | Kevin Correia | Kevin Correia | Paul Maholm | Heath Bell | 580 | 693 | -113 |
| 2009-09-21 | vs SDN | 148 | L 6-11 | 54-94 | 6 | 12,566 | Daniel McCutchen | Wade LeBlanc | Sean Gallagher | Jeff Karstens | | 586 | 704 | -118 |
| 2009-09-22 | vs CIN | 149 | L 4-10 | 55-94 | 6 | 16,492 | Zach Duke | Johnny Cueto | Johnny Cueto | Zach Duke | | 590 | 714 | -124 |
| 2009-09-23 | vs CIN | 150 | L 2-12 | 56-94 | 6 | 15,980 | Kevin Hart | Homer Bailey | Homer Bailey | Kevin Hart | | 592 | 726 | -134 |
| 2009-09-24 | vs CIN | 151 | L 1-4 | 56-95 | 6 | 15,892 | Charlie Morton | Bronson Arroyo | Bronson Arroyo | Charlie Morton | Francisco Cordero | 593 | 730 | -137 |
| 2009-09-25 | vs LAN | 152 | W 3-1 | 57-95 | 6 | 19,452 | Jeff Karstens | Jon Garland | Donald Veal | Jon Garland | Matt Capps | 596 | 731 | -135 |
| 2009-09-26 | vs LAN | 153 | L 4-8 | 57-96 | 6 | 35,605 | Paul Maholm | Randy Wolf | George Sherrill | Denny Bautista | | 600 | 739 | -139 |
| 2009-09-27 | vs LAN | 154 | W 6-5 | 58-96 | 6 | 26,831 | Daniel McCutchen | Clayton Kershaw | Matt Capps | Jonathan Broxton | | 606 | 744 | -138 |
| 2009-09-28 | vs LAN | 155 | W 11-1 | 59-96 | 6 | 16,696 | Zach Duke | Hiroki Kuroda | Zach Duke | Hiroki Kuroda | | 617 | 745 | -128 |
| 2009-09-29 | @ CHN | 156 | L 0-6 | 59-97 | 6 | 35,308 | Kevin Hart | Ryan Dempster | Ryan Dempster | Kevin Hart | | 617 | 751 | -134 |
| 2009-09-30 | @ CHN | 157 | W 4-0 | 60-97 | 8 | 34,362 | Charlie Morton | Ted Lilly | Charlie Morton | Ted Lilly | | 621 | 751 | -130 |
| 2009-09-30 | @ CHN | 158 | W 8-2 | 60-97 | 8 | 33,299 | Jeff Karstens | Carlos Zambrano | Jeff Karstens | Carlos Zambrano | | 629 | 753 | -124 |
| 2009-10-02 | @ CIN | 159 | W 3-1 | 62-97 | 6 | 16,288 | Daniel McCutchen | Justin Lehr | Daniel McCutchen | Justin Lehr | Matt Capps | 632 | 754 | -122 |
| 2009-10-03 | @ CIN | 160 | L 4-8 | 62-98 | 6 | 24,539 | Zach Duke | Johnny Cueto | Johnny Cueto | Zach Duke | | 636 | 762 | -126 |
| 2009-10-04 | @ CIN | 161 | L 0-6 | 62-99 | 6 | 20,940 | Jeff Karstens | Homer Bailey | Homer Bailey | Jeff Karstens | | 636 | 768 | -132 |